1. Field of the Invention
The present disclosure pertains to a method and apparatus for preventing liquid ingress from a humidifier into in a pressure support device, and, in particular, for preventing liquid ingress resulting from a tilting of the humidifier pressure support device.
2. Description of the Related Art
Pressure support devices configured to provide a pressurized flow of breathable gas to the airway of a subject are known. Humidifiers are included in some conventional devices in order to control the humidity of the pressurized flow of breathable gas that is generated. These humidifiers generally require storage of a reservoir of liquid, such as water. When conventional devices are transported, jostled, or improperly used, they may be tilted with respect to their intended operational orientation. This tilting may cause a flow of liquid from the storage reservoir into other areas of the device which may reduce the efficiency and/or effectiveness of the device, cause the device to stop working, damage the device, and/or have other undesirable consequences.
Existing humidifiers also need to contain a sufficient quantity of water so as to deliver enough moist air to a patient during a typical 8 hour sleep period. This requires that the water chamber be large enough to deliver therapy at worst case ambient conditions. Also, to greatly reduce or eliminate the chance of water damage to the therapy device, the water chamber is typically sized to accommodate the defined water volume during drop and rotation of the therapy device. This requires the water chamber to be larger in volume than what is required for therapy. This increase in chamber volume is typically 1.5 to 2 times the defined water volume, i.e. if the tank need to hold 325 ml of water for therapy requirements, the tank may need to be designed to hold up to 650 ml of water to eliminate water ingress back into the therapy device during misuse conditions. This large water volume requires a bigger footprint for the overall therapy system, adds weight and is harder to transport.
Furthermore, conventional humidification systems typically utilize a resistive heater to heat a large mass of water all at once. This bulk heating approach takes longer for the humidifier to heat up and uses more energy.